Did it make a difference to be in Vienna at the end of September or early to mid October since Vienna is the last leg of the tour? Does a week later for the tour really makes a difference since it is $200 cheaper. We rather have better weather than save the $200, but it would allow us to be in Switzerland a week later to avoid the crowds? We would like to visit Switzerland for about 7 days before the tour and stay a few days longer in Vienna after the tour.
Vienna is just up the road from where I live. The weather is a tad wetter but otherwise very similar to here. There is nothing different between 21 or 28 September. I mean if you look at the daily averages, maybe 2 degrees or something. But given the lack of predictibility of the weather 28 September is just as likely to be warmer than 21 September. If it saves you $200 go for it. If you arent pinched for time at the end, after 3 or 4 days in Vienna come visit. It really is a good time of year for lower altitudes of Austria and most every place south of Austria. My recommendation to friends and family is generally 15 September (to be free of the other tourists) till 15 October (as the weather is still very good - sweater at most). But even thats conservative as the outdoor cafes are generally open till the end of October. Heck, some are open now ..... brrrrrrrrrrr.